Method and system for analyzing uranium-silicon compound nuclear fuel expansion behaviors caused by fission gas

Abstract

The invention discloses a method for analyzing U3Si2 nuclear fuel expansion behaviors caused by fission gas. The method comprises the following steps: establishing a rate theoretical model for calculating uranium-silicon nuclear fuel gas atom diffusion; carrying out high-precision fitting on an experiment result based on different boundary conditions and environmental variables; calculating the size and the number of bubbles at different temperatures at different time, and calculating the fuel expansion rate caused by gas diffusion behaviors at different temperatures; and calculating the relationship between the fission density and the instantaneous fission rate at the expansion point, and calculating and analyzing the formation reason of bubble interconnection at the expansion point. Themethod can be used for analyzing the nuclear fuel expansion behavior caused by fission gas under the uranium-silicon nuclear fuel experimental reactor condition. An analysis result is reliable, repeatability is high, and implementation is easy.

Description

technical field [0001] The invention relates to the field of material science, in particular to a method and a system for analyzing the expansion behavior of uranium-silicon compound nuclear fuel caused by fission gas. Background technique [0002] The accident at the Fukushima nuclear power plant caused by the Great East Japan Earthquake and tsunami raised questions about the safety of oxidized nuclear fuels, which inspired the global development of a new type of accident-tolerant nuclear fuel (ATF) to replace the existing "uranium dioxide fuel-zirconium alloy". cladding” system to enhance the system’s tolerance to nuclear accidents. At present, uranium-silicon series nuclear fuels with a variety of compounds have entered people's field of vision. Uranium-silicon compounds have good high temperature stability under irradiation conditions, and have higher uranium density than UO2 (far more uranium) and thermal conductivity (comparable to uranium carbide); in addition, the m...

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Problems solved by technology

[0004] It is difficult to capture the diffusion of bubbles by experimental observation, and the traditional molecular dynamics simulation cannot be simulated for a long time due to the limitation of atomic vibration

The dynamic Monte Carlo or phase field crystal method can simulate long-term diffusion behavior, but it is difficult for the dynamic Monte Carlo method to create a complete catalog for complex systems, and the phase field crystal method mainly solves problems such as high temperature solidification near the melting point, the above The method has certain limitations for simulating long-term gas atom diffusion and nuclear fuel failure behavior.

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